Chain tensioners (sometimes called “tie down tensioners”) are commonly used to secure cargo during transport. A chain tensioner will typically comprise an apparatus with a hook at one end and a means for attaching a chain at the other. The chain may be attached to the cargo, while the hook may be attached to a tie-down ring on an aircraft or other form of transport. After the chain is initially attached between the chain tensioner and the cargo, a tensioning wheel on the chain tensioner may be rotated to effectively reduce the length of the chain tensioner, and thereby increase the tension on the chain. Later, the chain may be quickly released by manipulating a release handle on one side of the chain tensioner. Such chain tensioners are available from, for example, Davis Aircraft Products Co. (Bohemia, NY, USA), as well as others.
An unintended release of a chain by a chain tensioner is a very real hazard when utilizing these devices. Personnel moving about an aircraft may, for example, accidentally kick the release handle of a chain tensioner while that chain tensioner is actively securing cargo. If such an unintended release were to occur in an aircraft, a shift in cargo could suddenly place the center-of-gravity in a position where the aircraft is no longer controllable. In November 2011, the U.S. Department of Defense responded to this danger by publishing a specification for military chain tensioners that explicitly specifies: “The mechanism [for chain release] shall be designed in such a manner that inadvertent release of the mechanism by personnel moving about the aircraft does not occur” (U.S. Detail Specification MIL-DTL-26959H, 13 Nov. 2012).
For the foregoing reasons, there is a need for new chain tensioner designs that incorporate chain connection assemblies that minimize the chances of inadvertent releases.